1. Technical Field
The present invention relates to pistons for internal combustion engines, and more particularly to pistons having a cooling chambers.
2. Related Art
A piston assembly for an internal combustion engine generally becomes very hot during operation. And thus, the piston is subjected to relatively severe thermal stresses. For example, the crown of the piston is directly exposed to the most extreme heat in the combustion chamber. The challenges posed by extreme heating of the crown has become more severe with modern internal combustion engines due to increases in the thermal load on the parts resulting from increases in engine power output. Various mechanisms have been developed in an effort to cool piston assemblies. For example, a flow of lubricant can be directed to the underside of the crown from the crank chamber. It has been recognized as desirable in some arrangements to provide a chamber near the lower surface of the piston crown to provide an accumulating pool of lubricant for temporarily and intermittently cooling the piston crown. The lubricant from this pool can be splashed against the piston crown as the piston reciprocates in the cylinder bore. Such a lubricant reservoir may be provided by a part of the piston assembly which is integrally formed or cast with the piston main body itself or is welded thereto. And, although some efforts have been generally effective in providing the cooling to the crown region, advances are still sought, particularly with regard to economical aspects of fabricating the cooling chambers.